Mold



` which the mold members may be formed of f of the tube.

Patented Nov. 22, 1932 'UNM-De STATES ROBERT VW. sNYDEn, or AKRON, OHIO,AssIGNoitl 'ro wTHE GoonYnAn Tann .arianna COMPANY, or AKRON, OHIO, AconronArioN or OHIO I 'MOLD Application ilednAugiist 1,1929. SerialNi'o.` $52,607." A

rllhis invention relatesto themanufacture Aof hollow rubber articles anditA has particular relation to a mold foi` vulcanizingl inner tubes forpneumatic tires.

One object of the invention is to'provide a mold, for vulcanizing hollowrubber articles,of such construction that theheat employed in thevulcanizing process may be localized within the hollowv rubber articlebeing cured, without rapiddissipation thereof to the exterior of themold.

Another object of the'invention is to provide a mold for vulcanizinghollow rubber articles in which only small amount of metal need beemployed. i I

Another object of the inventionis to lprovide a method of manufacturingmoldsforV curing hollow rubber articles,by`means of different materialsbonded-together to provide a unitary assembly. Y

One method of manufacturing, inner tubes for pneumatic tires comprisesforming a tube of circular form from raw or uncured rubber andthereafter curing it under heat and pressure. Heat may be supplied tothe rubber either by admitting aheated `Huid through the valve stem of-the tube tothev interior thereof or by subjecting the outer surface'ofthe tube to contact with a heated portion of the mold.

In the veventthe heat is? supplied to the interior of the tube, it ishighly important that some means be provided for preventing dissipationof such heat through the tube and the parts of the mold retaining it. Asa a rule, the surface of the mold vcontacting with the inner tube mustbe composedv of metal in order that such surface may be madesufficiently smooth to prevent blemishes frombeing formed in theexterior surface The provision of a mold having a metallic surfaceeffectively united with an insulating material, so far as'known, hasnever been suggested.

According to this invention, it is proposed to make the sections of themold largely of receiving a part of an inner tube that whenlPreferably,-the surfaces ofthe wood defining the cavities are formedwith recesses and thereafter, by lmeans ofv a metal spraying device, thesurfacesof the sections defining the cavities areV coated with finelydivided metal, the particles of which effectively interlock witheachother. That metal sprayed into the recesses'in the'surface's ofthewood provides interlocking means for more effectively r'etainingthemetaland the wood together. Y vAfter the (surfaces defining'. the cavitieshave been so coated withmetal, the latter may be surfacedV by suitablemachinery in orderto provide afsmooth interior sur'- face for receivingan inner tube. i

/For abetter understanding of `the `invention, reference ma'yi now belhad to the' accompanylng drawing, forming aV part of the specilication,in which; c

Figure 1 is a'fragmentary cross-sectional view of a mold constructedaccording to the Y invention, and f 4 VFigure 21s 'afragmentarycross-sectional view of one of the mold ysectionsillustrating a method of coating aps'urface thereof with fwood,'rhavingaflow coeiicient of heat' conductivityL These Vsections areT providedrespective'ly, with annular [cavities r'13, and l14:

.the sections ar'edisposed` in theiroperative 'L which conjointly form acavity for receiving an inner tube. Onopposite'sides of the cavities,the .mold section 11 isprovided with faces 15 and 16 whichfare adaptedto abut correspondingY faces'cl? and"18 ,o`n the section y12. Adjacentthe'faces VV15' and 17, the

sections 11 and 12 are provided, respectively, 7

withfmetalli'c interlocking Irings 20 and 21 while adjacent thefa'ces 16and 18suchse`c-- tions are prvidedwith otherl metallicinterlockingrringsVQ and 26. The'mold sections are adapted web@ raid'(together-by brakes and-2S Secured", respectively po the outer sidesofthe sections 11 and l12 byscrews 30 and31;

These brackets, respectively, are kprovided With angle portions 32 and33 which extend axially .of the sections to positions adjacent thelocking rings 25 and 26. Other angle pori tionsftO and llfproject.radially-inwardly from the inner andfadjacent ends of the. portions V32,and 33, and are provided with slots 12l :and 4:3. Bolts 45, disposedinthe 'slots 42 and 48, and having nuts/16 Ontheir threaded? A ends,retain together the portions/10 and41.,

Vof the brackets 27 and 28, respectively, there by retaining the moldsectionsin ass-embledz relation. Y Y Y c Y 'lhe facesofthevmoldsections-ll` Yand 12 defining the cavitiesl?) and 14 areprovided .Y .With a plurality of recesses 50.V Also,"cylindrical grooves53 and 56 are provided in the sections V-11fjand 12' adjacent thesurfaces-15 and 16,v respectively,vvhile onV theoppositeV'siderofthe-sectionsadjacent the surfaces 16 andy 18, similar grooves57 and v58,' respectively, are provided.

Y *251 lThesurfacesof the .mold sections, defining` the cavities '13 and14 thenare coated With suitable machineryto? provide a smooth surfacefor receiving an inner tube.:V During Ythe l fas between-themetalsegments. r

'operation of spraying -Qmetal f onsuch sur- CS, Par-tof themetal*sorsprayel 'enters the recesse's' 50V inthemold-sectionsandfef'fects an efficient. vinterlocking means rbetween 1the metal coat and the mold sections. H Metalis also sprayed into thegrooves'53, V56, 57 and :58, tvhielnzwhen surfaced. ushvvith the facesv15,v V16 1 and V17 vand 18, :provide a close fit The spray gun'60 forsprayingfnietal in this manner operates essentially as follovvs :V ,Ametallic Wire such'as one composedof tin,

Y `is slovivly jfed through a tube at one point in which acetylene gasis'jburnin'gg- This melts the Wire.V Practically simultaneously With 1the melting of thel'wire, astream of airv of "high velocity is YVmetalwhich breaks itinto a ne spray.

directed against the molten spray ris directed through the endofthe gun,'"uponj-the article which is to be coated.A The Vsprayedmetalis notin amolten state when i with y'the surface upon which it it contacts ofmanufacture considerably.

`ferred form of, the :invention and have de'- strongly to such surfaceYnot only because of the-interlockingmeans provided by the metal intherecesses'f50,rbutlbyreason of the fact that the wood has a comparativelyporous atnd uneven surface due to the grain therein, e c.

-. From the foregoingy description, itis aps.

parent that a mold has been constructed which necessitates the use ofonly a small amount of metal thereby Vreducing the-expense Moreover,

owing tothe fact that the mold is composed largely of v vood,'aneffective and inexpensive insulating ,material ,constitutes a large 5part I thereof. The methodf'of manufacturing issimpleandinexpensivdandametallic lining may be applied to the cavitiesdefinedin the a mold, when in operation, effectively preventsdissipation of theV heat in the interior y kofzthevtube, therebyreducing Athe expense/of `manufacture as well asproviding a moreuniformlyhvulcanized product.4 i v Although l have illustrated only.lthe prescribed that form in" detail, it yvvillr be ap- .-m'old sectionsaccurately and efficiently. n VSuch parent to those skilledQin `theartthat the c inventionis not so limited, but thatV various modificationsymay be made thereinvvithoutv Vdeparting from thespiritofthe inventionorf Ina mold fora rubberVj article in ivvhichf',y

vulcanizingheat y-is supplied to the interior l of-the article, saidmoldhaving'a Ycavity for receiving the article, a ymetallic lining `forsaidjcavit'y,v means for vpreventing dissipa- 1 `tionofhe'at throughsaid lining,said means lcomprising Wood secured tosaid lining, and Yinterlocking projections and y recesses arranged respectivelyonsaidliningrand said .vvoodftofretainthelatter together.

.. Y Invvitnessvvhereofl have 'hereunto signed my name at Akron,

in` theAk county yof Summit and State of Ohio,rU.S. A., this 31st dayofJuly, 1929.l l j' '1 f f ROBERT W. SNYDER Y [This "applied r'and' hence,the panticles Yare not bound together by What' may be termedV y aWelding action, Instead,'the.particles` are I' inter-locked'mechanically rby reason of the` factthat the particlesarefso finethat'vvhen applied Vuponthe'v surface in the rformfof la fr Vspraytheyform'alunitary laye'rf ing thisY metal tothe surface of wood'inthe moldpreviouslydescribed,the'metaliadheres In' 'applyf

